The invention relates to compositions for the oxidative dyeing of keratin fibers based on aminopyrazole derivatives as well as new pyrazole derivatives.
Oxidative dyes have achieved considerable importance in the dyeing of hair. The dyeing is brought about by the reaction of certain developers with certain couplers in the presence of a suitable oxidizing agent.
In particular, 2,5-diaminotoluene, 2,5-diaminophenyl-ethyl alcohol, p-aminophenol and 1,4-diaminobenzene are used as developers. Resorcinol, 4-chlororesorcinol, 1-naphthol, 5-amino-2-methylphenol and derivatives of m-phenylenediamine are included among those couplers whose use is preferred.
Oxidative dyestuffs used for dyeing human hair are subject to numerous special requirements. For example, they must be unobjectionable in toxicological and dermatological respects and must enable the desired intensity of coloring. In addition, a favorable fastness to light, permanent waving, acids and rubbing are demanded of the achieved hair dyes. But, in every instance, such hair dyes must remain stable over a period of at least 4 to 6 weeks without being influenced by light, rubbing or chemical agents. Moreover, it is necessary that a wide assortment of various color shades can be produced by combining suitable developers and couplers. In particular, 4-aminophenol, by itself or in a mixture with other developers, is used in combination with suitable couplers to achieve natural and especially fashionable shades in the red range.
The developer 4-aminophenol which was chiefly used formerly for the red range of the color scale has recently been criticized with respect to its physiological tolerability, while more recently recommended developers such as pyrimidine derivatives are not entirely satisfactory with respect to coloring. The pyrazole derivatives described in DE-OS 21 60 317, e.g. 3-amino-1-phenyl-2-pyrazolone-5, provide only a shallow depth of color which is unusable in hair dyeing practice.
The 4,5-diaminopyrazoles described in DE-OS 38 42 892 are satisfactory with respect to color intensity, but they show disadvantages which impede their use as hair dyes, e.g. 3(5), 4-diaminopyrazole shows a slight sensitizing activity. Because mixtures of isomers, which can only be separated by chromatography, are produced during their production other compounds, e.g. 4,5-diamino-1-methylpyrazole or 4,5-diamino-1-benzylpyrazole, are difficult to prepare.
Therefore, it is an object of the present invention to provide an oxidative hair dye composition based on a combination of developers and couplers containing a developer for the red range which is very favorably tolerated physiologically, is simple to produce and, together with conventional couplers, dyes the hair in brilliant red color hues with a great depth of color.
It has now been found that the proposed problem is solved in an outstanding manner by a composition for the oxidative dyeing of hair based on a combination of developers and couplers containing an aminopyrazole derivative of the general formula (I) ##STR2## or its physiologically tolerated, water-soluble salts as developer, where R=hydrogen or an alkyl group containing from 1 to 4 carbon atoms and n=2 or 3.
The developers of formula (I), of which the 3-amino-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine (R=H, n=3), the 7-amino-2,3-dihydro-1H-imidazo[1,2-b]pyrazole (R=H, n=2), and the 3-amino-6-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine (R=CH.sub.3, n=3) are preferred, are to be contained in the hair dye composition in a quantity of approximately 0.01 to 3.0 percent by weight, preferably in a quantity of 0.1 to 2.5 percent by weight.
Although it would appear obvious in view of the advantageous characteristics of the novel developers described here to use them as the only developers, it is also possible, of course, to use the developers of formula (I) together with known developers such as 1,4-diaminobenzene, 2,5-diaminotoluene or 2,5-diaminophenylethyl alcohol.
The following known couplers are preferred for use as constituents of the hair dye composition described here: resorcinol, 4-chlororesorcinol, 4,6-dichlororesorcinol, 2-methylresorcinol, 2-amino-4-(2'-hydroxyethyl)aminoanisole, 2,4-diaminobenzyl alcohol, 2,4-diaminophenylethyl alcohol, m-phenylenediamine, 2,4-diamino-5-(2'-hydroxyethoxy)toluene, 5-amino-2-methylphenol, 5-amino-4-fluoro-2-methylphenol, 5-amino-2-ethyl-4-fluorophenol, 5-amino-4-methoxy-2-methylphenol, 2,4-diaminophenoxyethanol, 4-amino-2-hydroxyphenoxyethanol, 1-naphthol, 3-aminophenol, 3-amino-2-methylphenol, 4-hydroxy-1,2-methylenedioxybenzene, 4-amino-1,2-methylenedioxybenzene, 4-(2'-hydroxyethyl)amino-1,2-methylenedioxybenzene, 2,4-diaminophenetole, 2,4-diamino-5-methylphenetole, 4-hydroxyindole, 3-amino-5-hydroxy-2,6-dimethoxypyridine, and 3,5-diamino-2,6-dimethoxypyridine.
The coupler and developers can be contained in the hair dye composition individually or in combination.
The total quantity of combined developers and couplers contained in the hair dye composition described here is 0.1 to 5.0 percent by weight, preferably 0.5 to 4.0 percent by weight.
The developer components are generally used in approximately equimolar quantities with respect to the coupler components. However, it is not disadvantageous if the quantity of developers is somewhat larger or smaller.
Further, the hair dye composition, according to the invention, can contain other dye components in addition, e.g. 6-amino-2-methylphenol and 2-amino-5-methylphenol, as well as other conventional direct-dyeing dyestuffs, e.g. triphenylmethane dyes such as 4-[(4'-aminophenyl)-(4"-imino-2",5"-cyclohexadiene-1"-ylidine)-methyl]-2-m ethyl-aminobenzene monohydrochloride or Diamond Fuchsine (C.I. 42,510) and 4-[(4'-amino-3'-methylphenyl)-(4"-imino-3"-methyl-2",5"-cyclohexadiene-1"- ylidene-methyl]-2-methyl-aminobenzene-monohydrochloride or Leather Ruby HF (C.I. 42,520), aromatic nitro dyes such as 2-nitro-1,4-diaminobenzene, 2-amino-4-nitrophenol, 2-amino-5-nitrophenol, 2-amino-4,6-dinitrophenol, 2-amino-5(2'-hydroxyethyl)aminonitrobenzene, and 2-methylamino-5bis(2'-hydroxyethyl)aminonitrobenzene, azo dyes such as the sodium salt of 7-[4'-amino-phenylazo]-8-hydroxynaphthaline-4-sulfonic acid or Acid Brown 4 (C.I. 14,805) and dispersed dyes such as 1,4-diaminoanthraquinone and 1,4,5,8-tetraaminoanthraquinone. The hair dye composition can contain these dye components in a quantity of approximately 0.1 to 4.0 percent by weight.
Of course, the couplers and developers as well as the other dye components, insofar as they are bases, can also be used in the form of physiologically tolerated salts with organic or inorganic acids such as hydrochloric acid or sulfuric acid, or--insofar as they have aromatic OH groups--in the form of salts with bases, e.g. as alkali phenolates.
Moreover, other conventional cosmetic ingredients can also be contained in the hair dye composition, e.g. antioxidants such as ascorbic acid, thiogylcolic acid or sodium sulfite, as well as perfume oils, complexing agents, wetting agents, emulsifiers, thickeners and hair care materials.
The preparation form of the novel hair dye composition can be e.g. a solution, particularly an aqueous or aqueous-alcoholic solution. But the particularly preferred preparation forms are a cream, gel or emulsion. Its composition is a mixture of dye components and conventional ingredients for such preparations.
Conventional ingredients in solutions, creams, emulsions or gels are e.g. solvents such as water, lower aliphatic alcohols, e.g. ethanol, propanol, isopropanol, glycerol or glycols such as 1,2-propylene glycol, wetting agents or emulsifiers from the classes of anionic, cationic, amphoteric or nonionic surface-active substances such as fatty alcohol sulfates, ethoxylated fatty alcohol sulfates, alkyl sulfonates, alkylbenzene sulfonates, alkylbenzene sulfonates, alkyltrimethylammonium salts, alkyl betaines, ethoxylated fatty alcohols, ethoxylated nonylphenols, fatty acid alkanol amides, ethoxylated fatty acid esters, also thickeners such as higher fatty alcohols, starch, cellulose derivatives, vaseline, paraffin oil and fatty acids, as well as hair care materials such as cationic resins, lanolin derivatives, cholesterol, pantothenic acid and betaine. The aforementioned components are used in quantities which are conventional for such purposes. For example, the wetting agents and emulsifiers are used in concentrations of approximately 0.5 to 30 percent by weight, the thickeners are used in quantities of approximately 0.1 to 25 percent by weight, and the hair care materials are used in a concentration of approximately 0.1 to 5.0 percent by weight.
Depending on the composition, the hair dye composition, according to the invention, can react in a slightly acidic, neutral or alkaline manner. In particular, it has a pH between 8.0 and 11.5, and it is preferably adjusted with ammonia. However, organic amines such as monoethanolamine and triethanolamine, or inorganic bases such as sodium hydroxide and potassium hydroxide can also be used.
When used for the oxidative dyeing of hair, the hair dye composition described above is mixed immediately prior to use with an oxidizing agent and a quantity of this mixture sufficient for the hair dyeing treatment, generally approximately 60 to 200 g depending on the fullness of the hair, is applied to the hair. Hydrogen peroxide or its addition compounds in urea, melamine or sodium borate in the form of a 3- to 12-percent, preferably a 6-percent aqueous solution chiefly come under consideration as oxidizing agents for developing the hair dye. If a 6-percent hydrogen peroxide solution is used as oxidizing agent, the weight ratio of hair dye composition to oxidizing agent is 5:1 to 1:2, but preferably 1:1. Larger quantities of oxidizing agent are used in the hair dye composition chiefly with higher concentrations of dyestuff or when a more intensive bleaching of hair is intended simultaneously. The mixture is allowed to act on the hair at 15.degree. to 30.degree. C. for approximately 10 to 45 minutes, preferably 30 minutes; the hair is then rinsed with water and dried. The hair is washed with a shampoo after this rinse, if necessary, and possibly re-rinsed with a weak organic acid such as citric acid or tartaric acid. The hair is then dried.
The production of the developers according to the invention has not yet been described in publications.
The production of 7-nitro-2,3-dihydro-1H-imidazo-[1,2-b]pyrazole is described in A. J. Goddard et al., Anti Cancer Drug Design 2, 235 (1987). It is based on a 5-amino-4-cyano-1-(2'-hydroxyethyl)pyrazole, from which the desired compound is obtained after ring closure and subsequent nitration with a yield of approximately 10%.
On the other hand, a better yield is obtained by alkylation with dibromoalkanes and subsequent reduction of the nitro group of the 3(5)-amino-4-nitropyrazole described in H. Dorn et al., Liebigs-Ann. Chem. 707 (1967), 141-146.
The compounds according to the invention can be produced in a manner analogous to the method described above.
The developers of formula (I) are used in the hair dye composition either as free bases or in the form of their physiologically tolerated salts with inorganic or organic acids, e.g. hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, propionic acid, lactic acid or citric acid. The compounds of formula (I) have good solubility in water. Moreover, they have an excellent shelf stability, particularly as constituents of the hair dye composition described here.
The hair dye composition, according to the invention, containing aminopyrazole derivatives as developers makes it possible to dye hair with excellent color fastness, particularly with respect to light, washing and rubbing, and the hair dyes can be removed again with reducing agents.
With respect to dyeing characteristics, the hair dye composition according to the invention offers possibilities reaching far beyond the substitution of conventionally used 4-aminophenols. It can produce brilliant red hues with extraordinary depth of color which cannot be achieved with current dye components. But apart from this application in the field of high fashion, natural color hues can also be produced by combining it with suitable couplers without requiring an additional developer of the p-phenylenediamine type.
The very good dyeing properties of the hair dye composition according to the present application can also be seen in that this composition makes it possible to dye gray hair that has not been chemically damaged beforehand easily and with good covering power.
The subject matter of the present patent application is further directed to novel pyrazole derivatives of the general formula (II) ##STR3## where R.sup.1 is hydrogen or an alkyl group containing from 1 to 4 carbon atoms, n=2 or 3, and X is a nitro or amino group, where 7-amino-2,3-dihydro-1H-imidazo[1,2-b]pyrazole, 3-nitro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine, 3-amino-4,5,6,7-tetrahydro-pyrazolo[1,5-a]pyrimidine, 3-nitro-6-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine, and 3-amino-6-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine are mentioned in particular.